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(NoMoNel.) E. Dl LEA'V'ITT, J1',

. DIRECT ACTING GOMPOUND ENGINE. No. 283,261. Patented Aug. 14, 1883.

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UNITEDV lSTATES PATENT OFFICE.

ERASMUS ,DARWIN LEAVITT, JR., VOF CAMBRIDGE, MASSACHUSETTS, AS- SIGNORTO DAUPHIN S. HINES, VILLIAllIA. PERRY, AND CHARLES C. VORTHINGTON, OFNEW YORK, N. Y. l

DIRECT-ACTING coMPoUND ENGINE..

SPECIFICATION forming `part of Letters Patent No. 283,261,ydatedlinguist 14, 1883.

Application filed June 27, 1883. (No model.)

T 'all whom, t may concern:

Be it known that I, ERAsMUs DARWIN LEAvrr'r, Jr., a citizen ofthe UnitedStates, residing in the lcity of Cambridge, county of Middlesex, andState of Massachusetts, have invented certain new and usefulImprovements in Direct-Acting Compound Engines, fully described andrepresented in the following specication and the accompanying drawings,forming a part of the same.

This invention relates to a direct-acting pumping-engine of the generalconstruction of that` shown and described in United States LettersPatent N o. 24,838, and known as the IVorthington Duplex Pumping-Engine.7

y In order to secure the successful operation of engines of this class,the two following conditions must be maintained: First, a uniform ornearly uniform propulsive powerA must be exerted during the entirestroke of the engine, and,second,the propulsive energy of the steam mustbe so divided that' each side of the engine will develop one-half of thetotal power. The first of these conditions is imposedby the fact that nobalance-wheel is used, and that the load upon the pistons or plunger-sof the pumps is uniform,or nearly so,throughoutthe entire stroke, sothat any considerable falling off of the power applied to thesteam-pistons would result in the slowing and final stopping of theengine before it had reached the end of its stroke. The second conditionis imposed by the necessity of having the plungers or pistons of bothpumps of the same size, which is necessary in order to secure a steadyand uniform discharge of water.

It is well known to those familiar with the science ofsteam-.engineering that steam can be most economically used at acomparatively high pressure, and also that, in order to utilize thelargest proportion of the power generated, it is necessary to use thesteam expansively. This principle of using steam has heretofore beenapplied to this class of engines in three ways: rst, by providing eachside of the en!` gine with one high-pressure cylinder and oneexpanding-cylinder, each high-pressure cyl,

iider receiving steam from the generator, second, by providing one sideof the engine with onehigh-pressure cylinder and the other side with onelow-pressure cylinder, a tank being interposed between'thc two, as shownand described in United States Letters Patent No. 116,131;` and, third,by providing one side of the engine with, one high-pressure cylinder andone expanding-cylinder, and the opposite side with one expandinglow-pressure cylin der, as shown and described in United States LettersPatent No. 251,780. In the iirst and `second of these organizations theuse of `only two cylinders and the necessity of umaintaining a uniformor nearly uniform propulsive power throughout the entire stroke renderedthe amountof expansion permissible comparatively small, and thus to agreat` degree derprived the engine of the benefits of this principle ofusing the steam,A while in the third y organization it was foundimpossiblev to secure one of the essential features of an engine of thisclass-that is to say, the equal division of the propulsive power betweenthe'two sides of the engine.

It is the object of the present invention to produce an organization inwhich high rates of expansion will be permissible without violatin g theconditions specified as to distribution and division of power, so thatsteam may be .introduced at a comparatively high initial pressure andexhausted only after its expansive energy has been nearly or quiteexpended.

To this end the invention consists in a direct-acting duplex engine, thecylinders of which are arranged and combined in the man-v nerhereinafter described and pointed out.

In 'the accompanying drawings, Figure 1 is 'a plan view of an engineembodying thexinvention, and Fig. 2 is aside elevationlof the same.

Referring to the drawings, it is to be understoodthat 1 is ahigh-pressure cylinder, and

4 an expanding low-pressure cylinder assoaV ciated therewithl to formone side of the duplex engine. These cylinders are provided with theusual steam-chests, 5 6, the valves of which may be operated by a singlerod, 7, as shown, said rod being connected in any convenient manner, asby the rock-shaft 12 and gine it not only becomes possible to divide therock-arms 13 14, with the piston-rod 15 of the opposite side of theengine.

Ihe second side of the engine, like the first, consists of twocylinders, 2 3, both of which are expanding-cylinders. These cylindersare provided with the usual steam-chests, 8 9, the valves of which areor may be operated from a single rod, 10, connected bya rock-shaft, 16,

and rock-arms 17 18 with the piston-rod 19-ofV the iirst side of theengine.

The steam-chests 8, 8 9, and 9 6 are connected by pipes 20, 21, and22,arranged substantially as shown, the pipes 2O and 22 being stated asvfollows: rlhe steam will be admitted through the pipe 11 to the cylinder1, .where it will act upon the piston at its full pressure throughoutthe whole or nearly the whole stroke. mcnces its return-stroke the steamalready in the cylinder will pass out through the pipe 20 and enter thetank 23 at a reduced pressure, and at the same time steam will beadmitted from the tank to the cylinder 2. thus admitted from the tankwill act upon the piston in said cylinder at its full pressure duringthe whole or nearly the whole stroke, after which, upon thereturn-stroke of the piston, it will pass `through the pipe 21 tocylinder 3, where it will act expansively upon the piston of thatcylinder. After performing its work in cylinder 3 the steam will passout through the pipe 22 and enter the tankA 24 in a still furtherexpanded condition. Fromthe tank 24 the steam will pass to the cylinder4, where it will perform its final work, after which it will passthrough the pipe 25 and enter the condenser or the open air at a verylow pressure.

By means of the organization just described it will be seen that thesteam is used expansively at least three times-first in the cylinder 2,then in the cylinder 3, and lastin the cylinder 4-thereby making itpossible to receive the steam at comparatively high initial pressure,and iinally exhaust it at a very low pressure, thus utilizing itsexpansive energy to a much greater degree than has heretofore beenpossible in this class of engines.y By using the steam expansively uponboth sides of the en- As the piston in this cylinder com- The steam.

total power generated equally between the two sides of the engine, butthe gradual loss of power incident to high ratios of expansion is sodistributed that practical uniformity of speed and power is obtainedthroughout the entire stroke of the engine.

The several cylinders will, of course, be so proportioned with relationto each other as to secure the results specified, the proportions shownin the drawings being only approximations for the purpose ofillustrating the principle of the invention.

In some cases it maybe found desirable to employ more than two cylindersupon each side ofthe engine. This can be done upon the principle justset forth without departing from or losing the advantage of theinvention. While in the present case the two cylinders on each side ofthe engine are shown as arranged upon the same axial lines, such anarrangement `is not necessary. The well-known annular form in which onecylinder surrounds the.

other may be adopted, or they may be arranged in any other convenient ordesirable position.

What I claim is- 1. The combination, with two compound engines arrangedto form the two sides ofa duplex engine, of connections whereby thesteam after being used in one side of the engine is conducted to andused in the second side of the engine, and then returned to and used inthefirst side of the engine, substantially as described.

2. The combination, with two compound engines arranged to form the twosides of a duplex engine, of tanks 23 24 and connections whereby thesteam after being used in one side of the engine is conducted to andused in the second side of the engine, and then returned to and used inthe first side of the engine, substantially as described.

3. The combination, with two compound engines arranged to form the twosides of a duplex engine, of connections whereby the steam after beingused in one side of the engine is IOO conducted to and used in thesecond side of the ERASMUS DARWIN LEAVITT, JR.

Witnesses:

- Gno. H. Cox,

J. S. CooN.

